<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>标签选择器</title>
    <style type="text/css">
        h2 {
            color: green;
            font-size: 30px;
        }
    </style>
</head>
<body>
    <h2>CSS特点</h2>
    <p>CSS为HTML标记语言提供了一种样式描述。</p>
</body>
</html>